Are you thinking of buying a modified MR2 Turbo? It may be a fast way to get the power you always wanted without going through the effort of building one for yourself. It may also turn out to be a major case of buyer’s remorse. Here is a short checklist for power modifications (I don’t need to tell you about rust, salvage titles and all the other gotchas that come with buying any used car). It’s not complete by any means, but it might just keep you out of trouble.
If the owner claims that it is making gobs of power, don’t believe it unless you see a recent dyno chart from a reputable shop. Make sure the car is exactly in the same trim it was dynoed. It’s too easy for the seller to pull a few critical pieces off and replace them with parts that aren’t up to the task. Find out the fuel and boost level it was dynoed at. If you want 300rwhp all the time, don’t purchase a setup that made 310rwhp at 25psi on race gas. Better yet, pay a good local shop for a baseline and remove all doubts.
Check the wiring throroughly. I cannot stress this enough. Pull out the trunk liner, look under the engine lid, look under the dash, pull off the center console the kick panels and inspect the inside of all the fuse boxes. Deduct big money for every T-tap you see. Be particularly wary of S-AFC, boost controller, EMS and piggyback installations that cut and splice into the stock wiring. People have paid me for tons of hours of wiring work just to get badly hacked up wiring removed and the original Toyota harnesses put back to a reliable state. Also pay close attention to how the wires are routed. In many cases inexperienced installers wire a boost controller so the only way to pull the engine harness out of the trunk to drop the engine is to cut the wires. Of course, these same installers use a single color wire so you cannot easily tell one from the other. If you see loose, naked wires running around all over the engine bay and/or the trunk, stay away from the car. Speaker wire in the engine bay? God forbid! What about unused connectors for removed stock equipment? These should all have been carefully taped up with electrical tape to prevent unwanted shorts or water damage. Inspect aftermarked fan and pump wiring carefully. Are they getting their power supply from the right place? Are there fuses close to the power source or is the entire setup ready to light off like a dry christmas tree tossed in a bonfire?
Look for missing bolts or bolts that don’t look OEM. You can expect to see non-Toyota bolts on aftermarket kits, but having these all over the motor is a sure sign of shoddy work done by an inexperienced or inattentive person. Are the bolts on the exhaust system stainless or are they rusting in place? Is the distributor or fuel rail held on with just one bolt? Are any nuts or studs on the manifolds missing? If yes, you might want to give the car a pass.
Are there missing parts? Is the timing belt cover missing? If so, I’ll bet the idler pulleys are rusted to hell. What about one or more of the engine grounds? Are the heat shields between the turbo and the gas tank missing? What about the battery? Is that puppy strapped down with the stock bar or is it ready to keep you off the track at your first track event? Are all the plastic undercovers on the car there and are they all held by more than one or two bolts? Missing parts are a sure sign that the car was not modified by somebody who paid attention to details. Some parts should be missing (like the cruise control–both units, not just the actuator) but other things should be there regardless. At the very least, make a list of the missing parts, get a quote for them deduct the cost of replacing them from the asking price.
Were holes made through the firewalls to get fuel or water lines routed? Obviously somebody never heard of bulkhead connectors or was too cheap or lazy to use them. You should deduct big time, especially if the holes were made with a sawzall.
Do the modifications make sense? If they are making 350rwhp on a stock IC, you need to be moving right along. Unfortunatelly, unless you trust the guy who built the car like a brother, you need to do your homework or at the very least run the mods list past someone who knows what they are doing to have it critiqued.
Is there a turbo kit? You better take a very close look. Is the center section properly clocked? Most turbo manufacturers specify that the oil feed must be no more than 5-10 degrees off vertical. If the oil feed is visibly clocked to one side, the turbo is probably already damaged. Start the car and warm it up. Do you see any visible signs of smoke? Do you smell any oil in the exhaust? Pull off the downpipe and see it there is any oil there. Check the shaft for play. What about the quality of the lines and the installation? Are there bolts or fasteners missing? Are the welds good? Did they clamp stainless steel braided lines on with hose clamps? Are areof the fittings loose or visibly leaking? All these point at a poorly assembled kit or an inexperienced installation job. Proceed with caution.
Take a close look at the vacuum lines, clamps and hoses. Are they in good shape or rotted and ready to pop off and either strand you or cause the overboost event that starts a new motor build? Are there clamps on all the vacuum lines that might see boost? What kind of shape are the turbo hoses in? Do the intercooler pipes and their routing look well thought out? My favorite was the car that came in with a silicone hose clamped right onto a smaller diameter silicone hose. Are there strange transitions between different diameters in places where they don’t need to be? Are there more turns in the pipes than you encountered at your last hill climbing event?
A leak down test is a good idea on a used car, but it is essential before you put down big money on a modified turbo setup. The 3S motor may be non-inteference, but with higher lift aftermarket cams the possibility of bent valves is there and too many shops simply don’t know what they are doing when they try to degree cams. Pull off the valve cover and check valve clearances. A well built motor will be on the tight end of the spec. A loosy-goosy set of measurements within spec but all over the map are a sign of either an older setup way past its prime or a poorly built head.
If the seller doesn’t allow you to perform these tests on the setup then take a pass. Don’t pay top dollar for somebody else’s mistakes. It’s better to pass up a deal than to get stuck with your next living nightmare.
If everything looks good, ask yourself honestly if the car is going to be enjoyable to drive for more than a few minutes. Is the fuel pump or the air-to-water intercooler pump so loud that you can hear it over the motor? Does the motor shake your seat so hard that you see blood on your next visit to the urinal? Is the car going to attract unwanted attention from law enforcement in your area even when you are granny driving? Is the clutch so hard that you end up with a left leg twice as strong as the right one after a couple weels of driving it? These things may be expected on a 600rwhp setup, but hardly warranted at the 300rwhp level.
This documentation in no way replaces the Toyota MR2 Repair Manuals. The purpose of this content is only to provide supplementary information to fellow MR2 enthusiasts. Midship Runabout and its contributing authors will not be held responsible for any injury or damages that may occur as the result of practicing any of the methods or procedures described within this website. Article and photo submissions are property of the contributing author.